Torque converters have been known and used in combination with automatic transmissions of automobiles for quite some time. Generally, a torque converter consists of a housing, an impeller or pump, a turbine, a stator containing a one-way clutch, and a lock-up clutch.
The impeller is hemispherical with an outer wall having inner and outer surfaces, and a plurality of vanes radially mounted to the concave inner surface of the impeller wall. The turbine is rotatably mounted within a back wall, and also contains a plurality of vanes opposite the impeller vanes. The impeller wall is welded to the converter body to form an enclosed housing for the torque converter. The stator is located between the impeller and the turbine. The impeller has an input shaft operatively connected to the engine drive shaft. The turbine has an output shaft attached to the transmission input shaft so as to rotate the output shaft of the transmission.
Many improvements have been made to torque converters to improve operation and efficiency. For example, see Applicant's patent, U.S. Pat. No. 6,996,978, relating to an improved stator for the torque converter. Also, see the General Motors patent, U.S. Pat. No. 6,959,239, which discloses a cooling control for a torque converter; the Nissan patent, U.S. Pat. No. 7,264,574, which discloses a control device for the torque converter lock up; and the Daimlerchrysler published application, U.S. Publication No. 2008/0016859, which relates to augmented output method and apparatus for a torque converter.
In use, fluid, such as oil, is added into the torque converter housing. When the engine shaft rotates the impeller, the fluid starts rotating as well. As the rotation speeds up, centrifugal forces cause the fluid to flow outward toward the impeller vanes. The impeller vanes direct the fluid towards the turbine vanes, wherein the force of the fluid causes the turbine to rotate in the same direction as the impeller. The turbine shaft rotates the transmission shaft, which causes the vehicle to begin moving. The orientation of the turbine vanes directs the fluid towards the center of the turbine, where the vanes of the stator direct the fluid back towards the impeller, and the fluid cycle is repeated. Initially, the impeller will be rotating at a much greater speed than the turbine, which results in energy loss between input from the motor and output from the transmission. However, when the vehicle reaches a higher speed (over 40 miles per hour), the impeller and turbine will be rotating at approximately the same speed. At this time, a lock-up clutch will mechanically connect the impeller and the turbine so that they rotate at exactly the same speed to transfer 100% of the power through the torque converter.
The lock-up clutch is installed in front of the turbine. When engaged, the clutch will rotate with and lock together the rotational speeds of the impeller and the turbine. This is called the “lock-up operation.” Because 100% of the power from the engine is passing through the torque converter, the vehicle will obtain greater fuel efficiency. However, problems exist with current designs of torque converters, and more specifically, with the design of the impeller. Because the impeller and turbine rotate independent of one another and contain separate vanes, when the centrifugal force directs the fluid outwardly towards the turbine, the turbine vanes may not receive all of the fluid. The fluid may overshoot the turbine vanes, and end up in front of the lock-up clutch. This fluid leak into the lock-up clutch increases the amount of time before the torque converter is able to “lock-up,” or it may prevent lock-up all together. When the impeller and turbine are not locked together, heat is generated in the converter. The greater the load and RPM difference, the greater the heat generated. This heat is lost power, and results in a lower transmission life, performance and fuel economy.
Therefore, the present invention addresses an improvement in the art and provides a better method and means for the fluid to be directed from the impeller to the turbine in a torque converter for improved efficiency, reduced lock-up time, and enhanced fuel economy.
It is therefore a principal object, feature, and/or advantage of the present invention to provide an improved method and apparatus for increasing fuel efficiency in an automobile having an automatic transmission.
It is another object, feature, and/or advantage of the present invention to provide an improved method and apparatus for transferring a fluid from an impeller pump to a turbine in a torque converter.
It is another object, feature, and/or advantage of the present invention to provide an improved method and apparatus for decreasing the amount of time the torque converter will take to lock up.
It is another object, feature, and/or advantage of the present invention to provide an improved method and apparatus for increasing the life of a lock-up clutch.
It is another object, feature, and/or advantage of the present invention to provide an improved method and apparatus that is compatible with most automobiles having automatic transmissions.
Still another objective of the present invention is the provision of an improved torque converter impeller having a deflector for improved flow of fluid from the impeller to the turbine.
Yet another objective of the present invention is the provision of a deflector on a torque converter impeller to preclude fluid over-shoot of the turbine.